Dendrimer fluid purification system and method

ABSTRACT

A dendrimer complex comprising a dendrimer and an antimicrobial agent with the dendrimer complex placeable directly into a fluid to inhibit growth of microbes or rid the fluid of microbes. In a further embodiment of the invention the dendrimer complex is secured to a carrier, which is placed in a body of fluid and allowed to dispense the antimicrobial agent into the fluid. Once the antimicrobial agent is dispensed, the dendrimer complex can be removed and recycled to add functional groups to the dendrimer so that the dendrimer can be reused.

FIELD OF THE INVENTION

[0001] This invention relates generally to fluid purification such as byridding fluids of microbial activity and, more specifically, to use ofdendrimer complexes to rid fluids of unwanted microbial activity.

CROSS REFERENCE TO RELATED APPLICATIONS

[0002] None

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] None

REFERENCE TO A MICROFICHE APPENDIX

[0004] None

BACKGROUND OF THE INVENTION

[0005] The concept of dendrimer technology and particularly dendrimersare well known in the art. In general, a dendrimer is a large moleculehaving a sphere-like shape and includes a core with outer branches forholding functional groups.

[0006] Dendrimers are unique, highly branched, organic molecules thatrepresent a breakthrough in polymer synthesis. Dendrimers are consideredto be novel because of their size, shape, and physical or chemicalproperties. Dendrimers represent an example of synthetic organicmolecules having uniform size and 3-dimensional structures. A promisingfeature of dendrimers is that they can be synthesized to have variousinternal structure and various surface properties. Because of themultiple reaction sites on the dendrimer molecules they can be combinedwith a number of different compounds.

[0007] Dendrimers are considered nanotechnology since the size of adendrimer molecule is typically in the nanometer range. In general, thedendrimers are comprised of three components a) a core material; b) ahighly-uniform branched polymers attached in step-wise layers to thecore and c) a nano-scaled 3-dimensional surface structure, commonlyspherical. While the synthesis of dendrimers is known, it is oftentimesdifficult and time consuming, thus the cost of dendrimers can berelatively expensive costing thousands of dollars per pound. Thetechnology and use of dendrimers remains limited at least partly due tothe high costs of the dendrimers. However, various dendrimer patents andpublications on dendrimers include laundry lists of proposedapplications or uses for dendrimers.

[0008] An example of a proposed use of a dendrimer in “wound treatment”is shown in Balogh U.S. Pat. No.6,224,898. Balogh et al discloses thatan antimicrobial agent comprising a metal-containing compound isdistributed on or in a dendrimer polymer for applying to a specific typeof wound, namely, “burn wounds”. Balogh et al states his “dendrimersilver nanocomposite” is applied to a wound by a spray or is applied toa cloth substrate and then applied to a wound. While Balogh et al.conducts tests he concludes that his antimicrobial agent is effective“in vitro” for treatment of wounds.

[0009] While the dendrimers generally do not have any antibacterialproperties the Cooper et al. U.S. Pat. No. 6,440,405 discloses formationof a quaternary ammonium functionalized dendrimer that does derive itsantibacterial properties from the dendrimer itself. In Publication No US2002/022012 Cooper et al. goes on to propose “surface treatments” usinga dendrimer biocide-silver nanocomposite as an antimicrobial agent.Cooper et al. prepares his biocide-silver nanocomposite by reacting thedendrimer biocide disclosed in his 6,440,405 U.S. patent with a silvercompound. Cooper et al. then incorporates his biocide-silvernanocomposite into various surface coatings to provide the coating orsurface with antimicrobial activity. Cooper et al. points out the use ofthe dendrimer with biocide-silver nanocomposite as being effectiveagainst agents such as anthrax. Cooper et al. specifically points outthe incorporation of his dendrimer silver nanocomposite into “protectivecoatings or paints, personal products such as cosmetics, industrialproducts, hospital products, and sanitation of swimming pools and spas.”Cooper et al. goes on to point out that his dendrimer silvernanocomposite can be “immobilized onto the surface to create efficientantimicrobial surfaces for use as biomaterial, anti-fouling paints, andother similar devices.” Thus, Cooper et al. teaches the use of thebiocide-silver nanocomposite within the structure or some type ofcoating to make antimicrobial surfaces.

[0010] The Tomalia et al. U.S. Pat. No. 5,714,166 discloses the use ofdendrimers for “pharmaceutical and agricultural applications” Morespecifically, Tomalia et al discloses dense star polymers can beassociated with a bioactive agent, a diagnostic agent or atherapeutic/diagnostic agent. Tomalia et al. teaches the use of thedense star polymers in pharmaceutical and agricultural applications. Hespecifically points out the transporting of genetic material through acellular member and into a cellular nucleus with a dendrimer polymer.

[0011] The Tomalia et al U.S. Pat. No. 4,507,466 discloses the uses ofdendrimers for emulsifier for oil or water emulsions, as wet strengthagents in the manufacture of paper and agents for modifying theviscosity in aqueous formations such as paints.

[0012] The Tomalia et al. U.S. Pat. No. 4,694,064 discloses the use ofdendrimer in the production of molecular composites and as crystallinemodifiers for polymeric materials.

[0013] In the above references it is evident that the dendrimers ordendrimer biocides have been combined with various biocidal agents toproduce antibacterial products that can be incorporated into articles orcoatings to rid surfaces of bacteria. In contrast, the present inventionhas found that one can incorporate dendrimers with an antimicrobialagent directly into a fluid to control microbial activity in the fluidin order to render the fluid safe for either consumption or recreationaluses. In addition, the invention includes a fluid treatment method thatpermits one to rid or at least inhibit microbial growth in the fluid andwhen the dendrimer antimicrobial agent is spent permits one to removeand recycle the dendrimer for combining with fresh antimicrobial agents.

SUMMARY OF THE INVENTION

[0014] A dendrimer complex comprising a large scale molecule having anantimicrobial agent as a functional group with the dendrimer complexplaceable directly into a fluid to rid the fluid of microbes. In afurther embodiment of the invention the dendrimer complex is secured toa carrier, which is placed in a fluid and allowed to release theantimicrobial agent carried by the dendrimer directly into the fluid.Once the antimicrobial agent is spent, the dendrimer complex can beremoved and recycled to add fresh functional groups to the dendrimer sothat the dendrimer can be reused.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1A schematically represents two molecules with sites forfunctional groups;

[0016]FIG. 1 schematically represents the two molecules of FIG. 1 withfunctional groups secured to the outer branches;

[0017]FIG. 2 shows a container containing a fluid with a dendrimer withfunctional groups schematically illustrated in the bottom of thecontainer;

[0018]FIG. 3 is a dispenser containing a dendrimer with a antimicrobialagent for placing in a fluid;

[0019]FIG. 4 shows a carrier such as a grid or fabric with dendrimerswith functional groups secured to the carrier; and

[0020]FIG. 5 shows a bead like object having a plurality of dendrimerswith functional groups secured to the bead like object.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] Dendrimers are known in the art and generally comprise largesphere like molecules that have a core, a shell of internal cells and ashell of exterior cells with sites for functional groups. One of thefunctional groups used with dendrimers includes biocides, other includespecific materials. An example of dendrimer with a silver complex isshown in the Balogh U.S. Pat. No. 6,224,898, which is incorporatedherein by reference.

[0022] The present invention utilizes the dendrimer as a carrier for anantimicrobial agent to permit the dendrimer with the antimicrobial agentto be placed directly into a fluid environment or in a fluid, whichrequires purification for a variety of purposes including being consumedor used for recreational purposes. As used herein the term dendrimerdescribes a highly branched molecule having a number of sites forattaching functional groups thereto. A dendrimer complex describes adendrimer with a functional group attached to the dendrimer. Forexample, a dendrimer silver complex refers to a dendrimer with silversecured to the dendrimer. Similarly, a dendrimer metal ion yieldingcomplex refers to a dendrimer having a metal secured to the dendrimerwith the metal releasing metal ions when the dendrimer metal ionyielding material comes into contact with a fluid, such as water. Asused herein the term antimicrobial agent references to a material thatkills or inhibits the growth of microbes including bacteria and otherorganisms.

[0023]FIG. 1 schematically represents a first large scale sphericalmolecule 11 located proximate a second large scale spherical molecule12. Located on spherical shaped molecule 11 are a set of sites 11 awhere functional groups can be attached. Similarly, reference numeral 12designates a second spherical shaped molecule having a set of sites 12 afor securement of a functional group thereto. FIG. 1 representsdendrimers in a generally pre active state.

[0024] A reference to FIG. 1A illustrates the first spherical molecule11 with a set of functional groups 11 b secured to the sites 11 a onmolecule 11. Similarly molecule 12 contains a set of functional groups12 b secured to sites 12 a on the molecule 12. In the present invention,an antimicrobial agent, which comprises the functional group, is securedto the dendrimer for purposes of controlling or killing microbes in afluid. Examples, of specific types of materials useful in a fluid tokill microbes such as bacteria are metal ion yielding materials. One ofthe known metal ion yielding materials is silver chloride another issilver nitrate. Other metal ion yielding materials for use in waterpurification the for killing microbes can be a metal ion yieldingmaterial selected from the group consisting of zinc sulfate, zinccarbonate, zinc chloride, copper chloride, copper carbonate, coppersulfate, silver chloride, stannous chloride and stannic chloride. FIG.1A schematically represents the dendrimer complex for killing microbesby release of the functional groups from the dendrimer molecule.

[0025] A part of the present invention is a method of disrupting microbeproliferation comprising securing a ion yielding material to a dendrimerand then bringing the dendrimer containing the ion yielding material inion communication with a source of microbes, for example by placing thedendrimer with the ion yielding material into a body of fluid 15 asshown in

[0026]FIG. 2 to allow the ions to come into the presence of themicrobes. The body of fluid 15 can be recreational water such as foundin a spa, hot tubs and pools or it can be fluid intended for consumptionsuch as drinking water or it can be other types of fluids where thefluid requires purification such as by ridding or curtailing themicrobial activity in the fluid. Thus, in one embodiment the presentinvention comprises a method of disrupting microbe proliferation bysecuring an antimicrobial agent to a dendrimer and immersing thedendrimer containing the antimicrobial agent in a fluid containingmicrobes, such as found in a body of water, to control microbialproliferation and thus render the water drinkable or suitable forrecreational purposes.

[0027] In another method of fluid treatment one secures an antimicrobialagent to a dendrimer and places the dendrimer containing theantimicrobial agent into a fluid, which containing microbial activity,for sufficiently duration to rid the fluid of microbes. The fluid is notlimited to water and could be fluids such as drinkable juices or thelike. One then maintains the dendrimer containing the antimicrobialagent in the fluid for at least a time sufficient to control themicrobial activity. The dendrimer containing the antimicrobial agent canthen be removed and recycled by replacing the spent antimicrobial agent.

[0028] A further feature of the invention is that although the dendrimercontaining the antimicrobial agent can be removed from the fluid one canalso leave effective amounts of dendrimers containing antimicrobialagents in the fluids sufficient to kill the microbes in the fluidswithout having the antimicrobial agent or the dendrimer exceeding safelimits for human consumption or recreational use.

[0029] Another method of antiseptic treatment comprises forming a groupof dendrimers and securing a antimicrobial agent to each of the group ofdendrimers and bringing the group of dendrimers with the antimicrobialagent secured thereto into a source of microbial activity in a fluid sothat the fluid must flow around the dendrimer containing the functionalgroup. For example, one may want to kill microbes in body fluidsincluding blood by incorporation the dendrimer with the antimicrobialagent into the fluid by running the blood through a screen having adendrimer with an antimicrobial agent secured to the screen to therebyprovide for on-the-go killing of microbes in the body fluid as the bloodflows through the screen.

[0030] In another embodiment, the present invention comprises the methodof microbial treatment in fluids comprising securing an antimicrobialagent such as a biocidal active agent to a dendrimer and applying thedendrimer with the biocidal active agent to a carrier, bringing thecarrier with the biocidal active agent thereon into the presence of amicrobial active site, such as in a fluid, and maintaining the carrierwith the biocidal active agent in the presence of the microbial activesite for sufficient time to at least inhibit microbial growth.

[0031] To determine the antimicrobial potential of various dendrimercomplexes a dendrimer-silver complex was prepared using commerciallyavailable silver acetate with a dendrimer purchased from Dendritech,Inc. of Midland, Mich. After formation of the dendrimer-silver complextests were performed to evaluate the antimicrobial activity usingmicroorganisms of both Pseudomonas aerugenosa and E. coli The testprocedure is as follows:

EXAMPLE ONE

[0032] 1. Prepare an inoculum of the test organism by streaking theentire surface of agar plates by the standard method for colonyisolation, with E. coli (Nutrient Agar) and Pseudomonas (PseudomonasIdentification Agar). Incubate the streaked agar plates at 37° C. forapproximately 18 hours.

[0033] 2. Harvest all the growth on the test organism plates by floodingthe plates with 9.0 ml of sterile distilled water per plate. Wash theharvested biomass by centrifugation for 1 hour at 3000 rpm, discardingthe supernatant fluid, and resuspending the biomass in 9.0 ml of steriledistilled water. Resuspend harvested cell by vortex agitation for 1minute.

[0034] 3. Dilute 0.1 ml of the dendrimer-silver complex into 100 ml of0.1% saline and sterile using a 0.45 micrometer filter.

[0035] 4. Dispense 9.8 ml of the diluted complex to sterile test tubesand inoculate with 0.2 ml of the washed test microorganism as describedabove and mix.

[0036] 5. Incubate for 10 minutes and perform serial dilution's anddispense 0.2 ml of dilution to agar plates for microbial enumeration bythe spread plate method. E. coli was cultivated on Nutrient Agar (NA)and Pseudomonas was cultivated on Pseudomonas Identification Agar (PIA)

[0037] 6. Incubate agar plates overnight at 370C and perform enumerationon plates having between 30 to 300 colonies.

[0038] 7. Determine antimicrobial activity by taking the log differencebetween an untreated control and a plate of the same dilution treatedwith the test nanocomposite.

TEST RESULTS

[0039] Based on enumeration by the spread plate method, the untreatedPseudomonas control plate contained 1.94×10⁷ colony forming unit (cfu),equivalent to a logo value of 7.29. The Pseudomonas plate treated withthe dendrimer-silver complex contained 1.0×10⁵ cfu, equivalent to alog₁₀ value of 5. The log₁₀ different after 10 minutes of treatment is2.3 or more than 99% reduction in cell numbers between the control andthe treated plate.

[0040] The untreated E. coli had 1.3×106 cfu and the E. coli treatedwith he nanocomposite had less than 1×10⁵ for a log10 reduction of atleast 1.1 which is equivalent to a 90% reduction in cfu after 10minutes.

[0041] In contrast, testing with silver ions alone requires at least onehour to obtain a 1 log₁₀ reduction in cfu of the test organisms. Basedon the test results it was concluded that silver in the form ofdendrimer-silver complexes, when placed in a fluid environment, issubstantially more active as an antimicrobial substance than silver ionsalone, even though it is well known that the silver ions posses strongantimicrobial activity.

EXAMPLE TWO

[0042] A second sample of a dendrimer silver complex was tested againstvarious concentrations of silver nitrate against both E. coli andPseudomonas aerugentoas The experiment was performed as follows:

[0043] 1. Prepare an inoculum of the test organisms by streaking theentire surface of agar plates, by the standard method for colonyisolation, with ether E. coli or pseudomonas aerugentoas. The plateswere incubated at 370C for approximately 18 hours.

[0044] 2. Harvest all the growth on the test organism plates by floodingthe plats with 9.0 ml of sterile distilled water per plate. Wash theharvested biomass by centrifugation for 1 hour at 3000 rpm, discardingthe supernatant fluid, and resuspending in 9.0 ml of sterile distilledwater. Resuspend harvested cell by vortex agitation for 1 minute.

[0045] 3. Inoculate test plates with 0.2 ml with the test organismprepare as described above.

[0046] 4. Place sterile 6-millimeter blank paper Discs on test platesand saturate with 10 microliters of the test substances.

[0047] 5 Incubate the plates for 24 hours at 370c and report results asthe diameter of the zone of inhibition around the discs treated with thetest substances. The results are summarized below: TEST RESULTS E. ColiPseudomonas (diameter of Test Substance (diameter of inhibitory zone)inhibitory zone) 10.0% Silver Nitrate 11 6  7.5% Silver Nitrate 7 6 5.0% Silver Nitrate 6 6  2.5% Silver Nitrate 6 6  1.0% Silver Nitrate 96  0.5% Silver Nitrate 12 6 Complex I 11 10 Complex I dialyzed 17 8Complex II 13 9 Complex III 18 10

[0048] The tests results show the diameter of the inhibitory zone inmillimeters where the microbes were effectively destroyed. The testsreveled that the dendrimer silver complex has an enhanced antimicrobialactivity when compared to silver nitrate as evidenced by the largerdiameter inhibitor zones. The exact mechanism is not fully understoodbut reveals that the dendrimer silver complex not only has greatereffectiveness in killing microbes in fluids than well known metal ionyielding compounds but also acts more quickly than other metal ionyielding compounds that yield the same ion.

[0049] In the present invention various methods of deliver of thedendrimer complex containing the antimicrobial agent to the fluids areused. In one method the dendrimer complex containing the antimicrobialagent 31 is adhered to a small bead or fluid insoluble particle 30, suchas shown in FIG. 5, or other particle carrier that has sufficient sizeto be retained within a dispenser as shown in FIG. 3. Dispenser 20 has aset of openings 21 which are smaller than the dendrimer containingmaterial 22 within dispenser 20 to thereby retain the dendrimercontaining material 22 therein. By confining the dendrimer complex 22within the dispenser 20 the dendrimer complex 22 can be recycled andreused. The dendrimer complex 22 can be bonded to various material, suchas illustrated in FIG. 5, to maintain the dendrimer in a condition wherethey can be retained and recovered for recycling. By adhering thedendrimer to a fluid insoluble carrier one can maintain the dendrimer inthe fluid for purposes of fluid purification and then remove thedendrimer for recycling of the dendrimer.

[0050]FIG. 4 shows another method, wherein the dendrimer is adhered to alarger structure such as some type of flow through member 25 that comesinto contact with the fluid. For example, the dendrimer silver complex26 can be placed on a flow through carrier such as a filter, a cloth, amembrane or other porous material or non porous material arranged topermit fluid to flow therethrough, such as illustrated in FIG. 4. A flowthrough carrier allows the dendrimer complex to come into direct contactwith the fluid to be treated by flowing the fluid through the carrier.Although flowing the fluid through the carrier one can also immerse thecarrier in the fluid. For example, placement of a carrier such asmembrane or a fabric directly into a body of fluid such as water permitsthe dendrimer to yield the antimicrobial agent to attack the microbes inthe fluid as the fluid flows through the carrier.

[0051] In still another method the dendrimer antimicrobial complex isplaced directly in the fluid to be treated without adhering thedendrimer antimicrobial complex to a carrier. The dendrimerantimicrobial complex is useful in direct treatment all types of fluidsincluding body fluids, recreational fluids and drinking fluids. As thedendrimers lacks any known appreciable toxicity the incorporation andthe presence of the dendrimers in fluids, even those which are ingestedby humans, is possible. In addition, the amount of measurable metal ionspresent in the fluids that is sufficient to control microbes canactually be less than the amount of measurable ions present with aconventional non-dendrimer compounds that also yield metal ions. Thegreater efficacy of the metal ions deliverable from a dendrimer asopposed to a non-dendrimer enables the use of metal ions forantimicrobial purposes that might be effective in killing microbes butcould not be used because it requires antimicrobial levels in the fluidthat would exceed safe human levels.

[0052] Thus the present invention includes a method of disruptingmicrobe proliferation securing a ion yielding material, such as a metal,to a dendrimer, bringing the dendrimer containing an ion yieldingmaterial in ion communication with a source of microbes in a fluid tocontrol microbial proliferation therein.

[0053] The present invention also comprises a method of disruptingmicrobe proliferation securing an antimicrobial agent to a dendrimer,bringing the dendrimer containing the antimicrobial agent into proximityof a fluid containing microbes and maintain the dendrimer containing theantimicrobial agent in the fluid to control microbial proliferation inthe fluid.

[0054] The invention includes a method of killing bacteria in a body ofwater applying a dendrimer containing a water purification material suchas a bactericide to a carrier, placing the carrier with the dendrimer byimmersing the carrier with the dendrimer containing the waterpurification material in a body of water and allowing water to contactthe dendrimer containing the water purification material such as abactericide to release the bactericide therefrom to kill bacteria in thebody of water. In this method the dendrimer can be removed from the bodyof water after release of the water purification material and a freshwater purification material is releasable secured to the dendrimerfollowed by placing the dendrimer with the fresh water purificationmaterial back into the body of water to continue the water purificationthereof. While a water purification material is attached to thedendrimer includes antimicrobial agents such as bactericides other waterpurification materials such as clarifiers can also be secured to thedendrimer to enable one to deliver the water purification materials tothe fluids. If desired at least two water purification materials such astwo different antimicrobial agents can be secured to the dendrimer toprovide a wider range of effectiveness.

[0055] Thus the method of applying dendrimer containing a waterpurification material can be placed in recreational waters such as foundin a spa, a pool or a hot tub. A use of the dendrimer with antimicrobialproperties in drinkable fluids such as fruit juices functions to rid thejuices of harmful microbes.

[0056] A further feature of the dendrimer complex, for example thedendrimer silver complex is even though heavy metals such as silver areconsidered toxic in excess of 100 ppb one can use the dendrimer silvercomplex to kill microbes in the water yet not have the level of heavymetal considerably below the considered toxic levels simply because ofthe antimicrobial efficiency of the dendrimer silver complex is moreeffective at lower concentrations.

We claim:
 1. A method of disrupting microbe proliferation comprising:securing a ion yielding material to a dendrimer to form a dendrimercomplex; placing the dendrimer complex containing the ion yieldingmaterial in ion communication with a source of microbes in a fluid tocontrol microbial proliferation in the fluid.
 2. The method of claim 1wherein a concentration of ions deliverable by the dendrimer complex isless than an effective concentration of ions required when delivered bya nondendrimer.
 3. The method of claim 1 wherein the ion yieldingmaterial is a metal ion yielding material.
 4. The method of claim 2wherein the dendrimer complex carrying the ion yielding material issecured to a carrier retained within a dispenser to thereby retain thedendrimer for recycling.
 5. The method of claim 4 wherein the ionyielding material yields silver ions.
 6. A method of disrupting microbeproliferation comprising: securing an antimicrobial agent to a dendrimerto form a dendrimer complex; placing the dendrimer complex containingthe antimicrobial agent into a fluid containing microbes; andmaintaining the dendrimer complex containing the antimicrobial agent inthe fluid to control microbial proliferation in the fluid.
 7. The methodof claim 6 including the step of immersing the dendrimer complex withthe antimicrobial agent in the fluid.
 8. The method of claim 6 includingmaintaining the dendrimer complex containing the antimicrobial agent inthe fluid for at least a time sufficient to control the microbialactivity and then removing the dendrimer complex containing theantimicrobial agent.
 9. The method of claim 6 wherein the dendrimercomplex carrying the antimicrobial agent is placed in a drinkable fluidand the level of releasable antimicrobial agent is insufficient to causeharm to a person ingesting the drinkable fluid containing the dendrimercomplex carrying the antimicrobial agent.
 10. The method of claim 6wherein the dendrimer complex is bonded to a carrier.
 11. The method ofclaim 6 wherein the dendrimer complex is placed in a body of drinkingwater.
 12. The method of claim 6 wherein the dendrimer complexcontaining the antimicrobial agent is placed in recreational water. 13.The method of claim 6 wherein the dendrimer complex containing theantimicrobial agent is placed in a spa, pool or hot tub.
 14. The methodof claim 6 wherein the dendrimer complex containing the antimicrobialagent is placed in a drinkable juice to rid the juice of harmfulmicrobes.
 15. A method of killing bacteria in a body of watercomprising: applying a dendrimer containing a bactericide to a carrier;placing the carrier with the dendrimer in a body of water; allowing thebody of water to contact the dendrimer containing a bactericide torelease the bactericide therefrom to kill a bacterium in the body ofwater.
 16. The method of claim 15 including the step of applying thedendrimer containing a bactericide to a carrier comprises applying thedendrimer to a particle for placement in the body of water.
 17. Themethod of claim 15 wherein after the dendrimer releases the bactericidethe dendrimer is removed from the body of water and a fresh bactericideis applied to the dendrimer to replenish the bactericide.
 18. The methodof claim 15 wherein the dendrimer is used for a carrier for at least oneother water purification material where the other water purificationmaterial is selected from the group consisting of water clarifiers, pHadjusters and algaecides.
 19. The method of claim 15 wherein thedendrimer containing a releasable water purification material is placedin a pool, spa or hot tub.
 20. The method of claim 15 wherein at leasttwo water purification material are secured to the dendrimer.
 21. Themethod of claim 15 wherein the step of securing the releasable waterpurification material to a dendrimer includes reacting the releasablewater purification material with the dendrimer to form an ionic bondbetween the dendrimer and the water purification material.
 22. Themethod of claim 15 wherein the dendrimer is removed from the body ofwater after release of the water purification material and a fresh waterpurification material is releasable secured to the dendrimer followed byplacing the dendrimer with the fresh water purification material backinto the body of water to continue the water purification thereof. 23.The method of claim 16 wherein the particle is formed into a bead whichis made form a water insoluble material and the dendrimer is secured toan external surface of the bead.
 24. An agent for placement in a fluidcomprising; a dendrimer, said dendrimer having a plurality of reactionsites thereon; and a bacteria killing material adhered to the pluralityof reaction sites, each of said bacteria killing material separatelyreleasable from the plurality of reactions sites when the dendrimerhaving the bacteria killing material adhered thereto is placed in afluid.
 25. The agent of claim 24 wherein the dendrimer having thebacteria killing material adhered thereto is immersed in a body of waterto liberate the bacteria killing material into the water.
 26. The agentof claim 25 including a carrier and the dendrimer having the bacteriakilling material is secured to a carrier.
 27. The agent of claim 25including a dispenser that permits ingress and egress of fluidstherethrough to contact the dendrimer having a bacteria killing materialto thereby dispense bacteria killing material into the fluid.
 28. Awater purification article comprising: a water purification material; adendrimer having a plurality of reaction sites thereon, said waterpurification material ionically bonded to the plurality of reactionssties on the dendrimer so that when the dendrimer with the waterpurification material is placed in a body of water the waterpurification material is released from the dendrimer.
 29. The waterpurification article of claim 28 wherein the water purification materialis selected from the group consisting of clarifiers, bactericides andalgaecides.
 30. The water purification article of claim 28 wherein thewater purification material comprises a metal.
 31. The waterpurification claim 28 wherein the water purification material is an ametal ion yielding material selected from the group consisting of zincsulfate, zinc carbonate, zinc chloride, copper chloride, coppercarbonate, copper sulfate, silver chloride, stannous chloride andstannic chloride.
 32. The water purification article of claim 28 whereinthe water purification material secured to the dendrimer comprises ametal ion yielding material.
 33. The water purification article of claim28 wherein the water purification material comprises silver chloride.